Here's a link to a version of LW that doesn't use the zero g installer
http://baghira.han.de/~jum/LimeWire.html (Jens-Uwe Mager builds this directly from the source LW makes available to all, and has generously offered it to all OSX users). That will allow you to see if it's an installer/ java problem (it uses the Java 1.4.1 update that came with one of the Jag updates. You just have to drag the app from the .dmg you download to anywhere on your hard drive.

I guess you know how to do a clean install (search for anything containing "limew" to also find the preferences folder. Search for the invisible "zerog" file to get rid of that pref).

I have also just installed Java when I get some problems I can't explain. Here's the link: http://docs.info.apple.com/article.html?artnum=120197 It's a 30 MB download, so I tend to keep it around, but only takes a few minutes to install.

Well, there's a few more options to consider.